The invention relates to a video signal processing apparatus for converting the number of the horizontal scanning lines in a frame of an inputted video signal and for outputting a new video signal with the converted numbers of the scanning lines in the frame.
At present there are many kinds of computerized converting systems and the number of scanning lines in the frame of the image plane in the systems are different from each other. Therefore, when an image produced by one system is displaced in another system, conversion of the number of scanning lines in the frame are necessary. For example, when an image produced by a computer graphics (CG) system or computer aided design (CAD) system is displayed in a television receiver in a format of NTSC, PAL, SECAM, HDTV and so on, the number of scanning lines in the frame must be increased or decreased.
In the prior art, such a conversion is performed by an apparatus which is especially designed for one input system and another output system. Accordingly, the apparatus can not be available for conversion of the images of different systems. In other words, a special apparatus is necessary for each system conversion